Sauces for retortable food products

ABSTRACT

A sauce composition is provided which is suitable for preparing firm textured starch-containing or vegetable products wherein said products are retorted in the sauce. The sauce composition in addition to the normal ingredients of spices, flavors, water, and other compounds contains by weight 0.1%-24% polysaccharides having a MW w  in the range of about 3,600 and 250,000. These polysaccharides include starch hydrolysates, and other polysaccharides such as alginates and carboxymethyl cellulose.

This is a continuation of application Ser. No. 08/003,592, filed Jan.13, 1993, now abandoned, which was a division of application Ser. No.07/821,208 filed Jan. 16, 1992, now U.S. Pat. No. 5,204,135.

BACKGROUND OF THE INVENTION

It is commonly known that upon retorting in sauces starchy foods such aspasta, rice, or vegetables lose their structural integrity. The foodsbecome mushy, agglomerate and lose their structural appeal.

Firm or non-mushy macaroni, vegetable and rice textures are highlydesirable for consumer acceptance in retorted food products. However,due to the severe high temperature, pressure and length of heating, finetextural attributes of macaroni, rice and vegetables are difficult toachieve.

Various attempts have been made to overcome the textural problem inretortable foods. Most efforts have been directed toward reformulatingthe composition of the starchy food component of the retortable foodswithout reformulating the sauces in which the starchy food is admixed.While this approach has worked reasonably well, it has not entirelysolved the problem.

Less successful efforts have been attempted in engineering sauces usedin retortable foods in order to increase the firmness of the starchyfood or vegetable retorted therein. U.S. Pat. No. 4,597,976 discussesreformulating the sauce in order to improve the textural properties ofthe retorted food product. The '976 patent specifies acidifying thesauce to a pH of less than 4.6 to reduce retort time and thus limittextural degradation of the starchy component of the food product.

The present invention, a sauce which preserves the physical integrity ofstarchy foods and vegetables retorted therein is a great improvementover the existing art. Further, a sauce which does not requirereformulated starch components nor an acidified pH to enhance firmnessin retortable pasta, rice, and vegetables is new and unique. Theinvention sauce is most effective in preserving the structural integrityof foods which absorb significant amounts of water during retort.Accordingly, the invention works best when admixed with dehydrated ordried foods.

SUMMARY OF THE INVENTION

A sauce composition has been discovered which when used in retortablefood products in admixture with starchy foods and vegetables preservesthe structural integrity of the retorted starchy foods and vegetables.An advantage of this invention is to provide a product which has ahigher tolerance to retort conditions. It is yet another advantage ofthis invention to provide a sauce which when combined with a starchyfood or vegetable does not require the starchy food or vegetable to bereformulated in order to remain firm after retort.

The sauce of the present invention, along with spices, flavorings, andother ingredients normally included in sauces used with starchy foods orvegetables is comprised of about 0.1-20% polysaccharides by weight. Thepolysaccharides have a weight average molecular weight (MW_(w)) in therange of about 3600 to about 250,000. Examples of these compoundsinclude starch hydrolysates of 1 to 20 DE (dextrose equivalent) whichare normally called maltodextrins or compounds from the group of lowmolecular weight alginates or carboxymethyl cellulose (CMC).

Sauces prepared according to the present invention may be used forretorted foods such as spaghetti, vegetables with cheese sauces,Mexican-style rice foods, or gravies for stews or dumplings to name afew.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph illustrating the effect of maltodextrin-containingsauces on retorted pasta texture.

FIG. 2 is a graph illustrating the effect of maltodextrin-containingsauces on retorted kidney bean texture.

FIG. 3 is a graph illustrating the effect of alginate and carboxymethylcellulose-containing sauces on retorted pasta texture.

DETAILED DESCRIPTION OF THE INVENTION

The advantage of using the sauce of this invention is that when thesauce is combined with foods to be thermally treated the foods willremain intact without excessive stickiness and agglomeration and willremain firm until the time of mastication. The sauces of this inventionare suitable for retorting with starch-containing food components suchas rice, pasta and flour-based foods (dumplings). The sauces of thisinvention are also suitable for retorting with vegetables such aspotato, carrot, and beans, and may be used with any vegetable whosetextural quality is degraded during thermal treatment.

Maltodextrin as used in this invention is defined as starch hydrolysatesof less than 20 dextrose equivalents (DE) which correlates to a weightaverage molecular weight (MW_(w)) of greater than about 3600. Starchhydrolysates of greater than or equal to 20 DE have a MW_(w) of lessthan 3600 and are known as corn syrups. Maltodextrins of variousmolecular weights are available commercially and may be purchased forexample from A. E. Staley Manufacturing Company (Decatur, Ill.). Staleyreports the viscosity of 1 DE through 20 DE maltodextrin at about 25centipoise (cps) when in solution in water ranging from 10% to 30% byweight. Staley measured the viscosity with a Brookfield Viscometer,Model RV (Brookfield Engineering Labs, Stoughton, Mass.) at 100 degreesF. at 20 rpm after rotating for 30 seconds using spindle #1.

Examples of other polysaccharides suitable for this invention includealginates such as propylene glycol alginate or sodium alginate whichhave MW_(w) in the range of 50,000 to 125,000 and are derived fromalgae. According to the manufacturer's (Kelco of San Diego, Calif.)specifications, alginate of 75,000 MW_(w) has a viscosity of 1,200 cpswhen placed in 2% by weight solution in water at 25 degrees C. whenmeasured with a Model LV Brookfield Viscometer at 60 rpm with thespindle #4. Alginate of 125,000 MW_(w) has a viscosity of 7,000 cps whenmeasured under the same conditions with spindle #6.

Further examples of polysaccharides suitable for this invention includecarboxymethyl celluloses such as sodium carboxymethyl cellulose with90,000 to 250,000 MW_(w) which may be purchased for example fromAqualone of Wilmington, Del. According to Aqualone, carboxymethylcelluloses of 90,000 MW_(w) have a viscosity of 25-50 cps when placed in2% solution by weight in water and measured with a Brookfield Viscometerat 25 degrees C. with spindle #1 at 60 rpm after rotating for 3 minutes.Carboxymethyl celluloses of 250,000 MW_(w) have a viscosity of 400-800cps when placed in 2% solution by weight in water when measured withspindle #2 with a Brookfield Viscometer at 30 rpm after 3 minutes ofrotating.

Preferably, the sauce of the present invention is formulated such thatcompounds are added which increase the average molecular weight of thewater soluble components without becoming too viscous. To practice theinvention, greater than 0.1% by weight of a polysaccharide having amolecular weight between 3600 and 250,000 is added to the saucecomposition. The molecular weight of the compound cannot be so high thatthe sauce is no longer an effective plasticizer for the dry component.Conversely, the molecular weight cannot be so low that the sauce becomesunsuitably sweet for pasta, rice, and vegetable dishes. Preferably,between about 5% and 24% maltodextrin having a MW_(w) between 3600 and100,000 (1 DE maltodextrin) or between about 0.1% and 4% alginate havinga MW_(w) between 50,000 and about 125,000 or between about 0.1% and 4%carboxymethyl cellulose having a MW_(w) in the range of 90,000 to250,000 is added to the sauce. The invention anticipates that differentpolysaccharides may be combined in the sauce to reach up to about 20% byweight or in the alternative a single type of polysaccharide may beused.

Any type or flavor of sauce normally added to starchy foods orvegetables may be formulated in accordance with the invention. Examplesof such sauces include but are not limited to cheese sauces, tomatosauces, gravies and cream sauces. Likewise, any spices or flavoringsnormally included in starchy food or vegetable sauces may be added tothe invention sauce formulation. An example of a cheese sauce of thepresent invention which contains seasonings and spices is as follows:

    ______________________________________                                        Ingredient          % by Weight                                               ______________________________________                                        Water-Polysaccharide Solution                                                                     81.07                                                     Instant Starch      2.50                                                      Salt                0.40                                                      Cheese Sauce Powder 16.00                                                     Beta-carotene       0.03                                                      ______________________________________                                    

Instant starch may be purchased from National Starch Company(Bridgewater, N.J.), cheese sauce powder may be purchased from KraftGeneral Foods (Memphis, Tenn.), and beta-carotene may be purchased fromHoffman-La Roche (Clifton, N.J.). Generally, seasonings and spices maybe added to the sauce up to about 40% by weight of the sauce.

While not intending to be bound by theory, the following is put forth topossibly explain the favorable results of the present invention. Waterand water soluble compounds such as maltodextrins act as plasticizers tohigher molecular weight polymeric compounds such as starch and glutens.Adding polysaccharides of the MW_(w) of the invention to a retortablesauce increases the effective molecular weight of the plasticizingsystem which thereby reduces the sauce's plasticizing ability. Once theplasticizing ability is reduced, the diffusion rate of water into thestarchy matrix of the product during retorting is also reduced.Additionally, the gelatinization temperature of starch in the system isincreased which reduces the overall degree of softening during thermaltreatment. This approach is very effective for any food product whichtakes up significant amounts of water during a retort operation.Therefore, the invention is most effective in preserving the structuralintegrity of dehydrated foods since dehydrated foods are more capable ofabsorbing large amounts of water as compared to their hydratedcounterparts. In this invention, a dehydrated food is defined as a foodhaving a reduced moisture content as compared to the natural moisturecontent of the food.

EXAMPLES

The sauce of the present invention was added to pasta, rice, carrots,potatoes, and kidney beans to test the firmness after retort. ForExamples 1 through 4, 1 DE, 5 DE, and 10 DE maltodextrins (MW_(w) srange from 100,000 to 9,500) were added separately to water in theamounts up to about 18% by weight in order to make the sauces. Thesauces of Example 5 were prepared using up to about 2% by weight ofalginate (MW_(w) of 50,000 to 125,000), while the sauces of Example 6were prepared using up to about 2% carboxymethyl cellulose by weight(MW_(w) of 90,000 to 250,000).

For the pasta, rice and carrots, firmness measurements were done usingthe Kramer Shear Press (Kramer et al., "A Device for Measuring FoodQuality", The Canner, Feb. 3, 1951, pp 34-36) equipped with a loadingcell of 500 kg which was attached to an Instron Universal TestingInstrument (Model TT-C; Canton, Mass.). One to three replicates weremeasured on each product. All measurements were at room temperature (72degrees F.) and the crosshead speed was 5 inches per minute.

For the kidney bean samples firmness measurements were done as describedin Example 4 below.

The following Examples demonstrated that significant improvement in thetextural quality of the retorted starchy food or vegetable was obtainedwhen the sauce of the invention was added to starchy foods or vegetablesbefore retort. FIG. 1 and FIG. 2 are representative of the firmnessresults of retorting all starchy foods and vegetables admixed with thesauce of the invention. FIG. 1 reflects the firmness of pasta combinedwith maltodextrin-containing sauce and retorted. FIG. 2 reflects thefirmness of kidney beans admixed with maltodextrin-containing sauce andretorted. Similar firmness data resulted no matter what food was admixedwith the invention sauce and then retorted. Likewise, similar firmnessdata resulted no matter what polysaccharide was used to formulate thesauce of the invention as can be seen when comparing FIGS. 1 and 2 withFIG. 3. FIG. 3 shows the firmness of pasta when retorted in alginate andCMC-containing sauces.

Firmness of the food retorted in the sauce was dependent upon theconcentration of the polysaccharide placed in the sauce. The morepolysaccharide which was added to the sauce, the firmer the foodretorted therein became. Results coincided when maltodextrin, alginate,and carboxymethyl cellulose were used to formulate the sauce and admixedwith food before retort. Notably, all samples which containedPolysaccharide-containing sauces displayed marked textural qualityimprovement over the control.

EXAMPLE 1

The texture of retorted pasta was tested using a maltodextrin-containingsauce.

Pasta was pretreated by placing 33% dry pasta by weight in 67% water at190° F. and soaking the pasta for 3 minutes. Excess water was thendrained and the pasta was weighed. To the pasta 2% Soy oil by weight wasadded, the pasta was then tossed to coat. Sixty-five parts of each ofthe maltodextrin-containing sauces were then individually combined with35 parts of the pretreated pasta. A control sample was prepared in whichonly water was added to the pasta in the ratio of 65 parts water to 35parts pasta.

The pasta samples combined with the sauces were packaged into 1/2 pintMason jars and heated in a Mirro (Manitowoc, Wis.) stove top pressurecooker for 25 minutes at 15 PSI at about 250 degrees F. The retortedjars were removed from the cooker after 45 minutes of cool down time.

Kramer Shear Press firmness measurement as described above was performedon 140 grams of the pasta samples after overnight storage at roomtemperature and the results are shown in FIG. 1.

EXAMPLE 2

The textural quality of retorted rice with maltodextrin-containing saucewas tested.

Rice was pretreated by placing 33% dry rice by weight in 67% water at190° F. and soaking for 5 minutes. Excess water was drained and the ricewas weighed. 2% soy oil by weight of the rice was added to the rice andthe rice was tossed until coated. The maltodextrin-containing sauceswere then individually combined with the pretreated rice in the ratio of73 parts sauce to 27 parts rice. A control sample was also prepared inwhich only water was added to the rice in place of themaltodextrin-water sauce. Thus, the control consisted of 73 parts waterand 27 parts rice.

The rice samples combined with the sauces were packaged and retorted asdescribed in Example 1.

To test the firmness of rice, the Shear Extrusion Adaptor manufacturedby Food Technology Corporation (Rockville, Md.) with round shear cellwas added to the Kramer Shear Press. Firmness measurement was performedon 130 grams of the samples after overnight storage at room temperature.The results were similar to those obtained in Example 1 wherein the ricesamples combined with maltodextrin-containing sauces showed markedtextural improvement as compared to the control. Also, the higher themolecular weight of the maltodextrin which was added to the sauce, thefirmer the rice which was retorted therein.

EXAMPLE 3

The textural quality of retorted dehydrated carrots with amaltodextrin-containing sauce was also tested.

The sauces were individually combined with dehydrated carrot at theratio of 90 parts sauce to 10 parts carrot to form the samples. Acontrol sample was prepared in which only water was added to the carrotsin place of the maltodextrin-containing sauce, thus 90 parts water and10 parts dehydrated carrot were combined for the control.

The carrot samples combined with the sauces were packaged as describedin Example 1. The retort conditions were the same as Example 1 exceptthe carrot samples were only retorted for 10 minutes. Dehydrated carrotswere retorted for a shorter time because they are more sensitive toretort conditions than the other foods tested.

Firmness measurements were done on 175 grams of the carrot samples afterovernight storage at room temperature using a Kramer Shear Press asdescribed above. Results followed the same trend described in Example 3.

EXAMPLE 4

The textural quality of retorted kidney beans were tested using amaltodextrin-containing sauce.

Maltodextrin-containing sauces were added to dehydrated kidney beans inthe ratio of 50 parts kidney beans to 50 parts sauce. A control wasprepared in which 50 parts water was added to 50 parts kidney beans, nomaltodextrin was added to the control. Kidney bean samples combined withsauces were packaged and retorted as described in Example 1. Kidney beanfirmness measurements were done using the Stevens L.F.R.A. AnalyzerModel TA-1000 (Scarsdale, N.Y.). Ten beans from each sample were placedon a Platen with a wedge cut lengthwise into its surface. The bean waspositioned in the wedge so as to keep the bean steady when it was cut.

A plastic blade which was longer than the length of the bean and had abeveled edge was used to cut the bean. The operating mode of theanalyzer was normal and the crosshead speed of the blade was 0.5 mm/secwith the blade cutting 5 mm into the bean or through one cotyledon. Datawere recorded on a chart recorder with a chart speed of 20 cm/min. Peakforce reading in grams were taken from the highest peak after theinitial peak since the initial peak was thought to be the result ofbreaking through the skin and not a true measurement of the insidetexture of the bean. Results of the firmness measurements are summarizedin FIG. 2.

EXAMPLE 5

The textural quality of pasta after retort was tested usingalginate-containing sauces. Pasta was chosen as the sole example foralginate-containing sauces because retorted pasta historically causesthe largest textural problems of any retorted foods.

Pasta was pretreated as described in Example 1. Samples were prepared inthe ratio of 65 parts alginate-containing sauce and 35 parts pasta. Acontrol was prepared in which water was added in place of thealginate-containing sauce, thus the control consisted of 65 parts waterand 35 parts pasta.

The samples were packaged, retorted and firmness measurements were doneusing a Kramer Shear as outlined in Example 1. The result of admixing50,000-75,000 MW_(w) alginate with pasta and then retorting is shown inFIG. 3.

EXAMPLE 6

The textural quality of pasta after retort was tested usingcarboxymethyl cellulose-containing sauce. Pasta was chosen as the soleexample for carboxymethyl cellulose-containing sauces because pastahistorically causes the largest textural problems of any retorted foods.

Pasta was pretreated as described in Example 1. Samples were prepared inthe ratio of 65 parts carboxymethyl cellulose-containing sauce and 35parts pasta. A control was prepared in which water was added in place ofthe carboxymethyl cellulose-containing sauce, thus the control consistedof 65 parts water and 35 parts pasta.

The samples were packaged, retorted and firmness measurements were doneusing a Kramer Shear Press as outlined in Example 1. The carboxymethylcellulose-containing sauces followed the same trend as themaltodextrin-containing sauces with respect to the firmness of the foodretorted therein as shown in FIG. 3.

We claim:
 1. A retorted food product having a sauce component andstarch-containing and/or vegetable food component of preserved texturalqualities prepared by the method comprising the steps of:a) preparingsaid sauce component wherein about 0.1 to about 24% by weight of thesauce component is comprised of polysaccharides of MW_(w) between about3600 and 250,000, and between about 36% to about 99.9% by weight water;b) mixing said sauce with a vegetable and/or a starch-containing food inratios suitable for the food product; c) thermally treating said mixtureat a temperature greater than 212° F. under pressure for a period oftime adequate to sterilize said mixture; d) cooling said mixture whereinafter combination of said sauce with said food, and thermal treating ofsaid mixture, said food remains intact and firm without agglomerationuntil mastication.
 2. The composition of claim 1 wherein saidpolysaccharide has a viscosity up to about 7,000 cps when placed in 2%solution by weight in water at 25° C. at 60 rpm when measured with aBrookfield Viscometer with spindle #6.
 3. The composition of claim 1wherein said polysaccharide is selected from the group consisting ofstarch hydrolysates of 1 DE to 20 DE with a MW_(w) between about 100,000and 3,600.
 4. The composition of claim 1 wherein the polysaccharide isalginate with a MW_(w) between about 50,000 and 125,000.
 5. Thecomposition of claim 1 wherein the polysaccharide is carboxymethylcellulose with a MW_(w) between about 90,000 and 25,000.
 6. Thecomposition of claim 1 wherein said sauce further comprises up to about40% by weight flavorings and spices.
 7. The composition of claim 6wherein said flavorings and spices are selected from the groupconsisting of salt, pepper, cheese sauce powder, meat flavorings, onionpowder, tomato flavoring, cilantro, oregano, parsley, basil, chilipowder, taco flavoring, lemon flavoring, garlic powder, and cayennepepper powder.
 8. The composition of claim 1 wherein saidstarch-containing food is selected from the group consisting of pasta,rice, and dumplings.
 9. The composition of claim 1 wherein saidvegetable is selected from the group consisting of potatoes, carrots,and beans.
 10. The composition of claim 1 wherein said sauce compositioncomprises about 0.1 to about 24% polysaccharide having a MW_(w) betweenabout 3600 and 250,000, up to about 5% starch, up to about 0.5% salt, upto about 40% cheese sauce powder, up to about 0.1% Beta-carotene, saidsauce having a A_(w) of greater than 0.92.